Peyton Manning's future beyond this season will be determined by the results of an offseason exam on his surgically repaired neck, sources familiar with the star quarterback's mindset told ESPN Senior NFL Insider Chris Mortensen.

Despite setting NFL single-season records for passing yards and touchdowns in 2013 with the Denver Broncos, Manning will undergo the physical exam in March, as mandated by his contract, the sources told Mortensen.

If the exam reveals that his neck is stable, Manning plans to return to the Broncos in 2014, regardless of how Denver fares this postseason, according to sources.

But if there is an increased risk of injury, Manning will be forced to decide whether to retire, sources said.

The 37-year-old Manning raised speculation about his future this past week when he said, "The light is at the end of the tunnel for me, no question." The four-time league MVP made the comment leading up to Denver's AFC divisional playoff game Sunday against the San Diego Chargers.

But neither a Super Bowl victory nor another playoff disappointment will impact Manning's decision on whether to play in 2014, sources told Mortensen.

Manning and the Broncos are a year removed from last January's crushing playoff loss to the Baltimore Ravens, who rallied for an improbable overtime upset in Denver. But the Broncos went 13-3 this season largely in part to the record-setting play of Manning, who passed for 5,477 yards and 55 touchdowns.